Temperature-Induced Reversible Phase Transition with Switchable Dielectric Response in a A2BX4-Type Hybrid Compound: [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3)

Low-symmetric quasi-spherical cations have been widely used in halogenometallate hybrids to increase the incidence of stimulus-responsive crystal structures. In this paper, we successfully used triethylmethylammonium bromide and cadmium bromide for self-assembly to obtain a A(2)BX(4)-type hybrid compound [TEAMA](2)[CdBr4] (TEAMA=(CH3CH2)(3)NCH3, 1) showing phase transition temperature (T-c) of 333 K above room temperature. Various-temperature structures of 1 have been measured by X-ray diffraction. We conclude, the phase transition property of 1 induced by thermal stimulation stems from the thermal ellipsoids of the [TEAMA](+) become strikingly larger with the increase of the temperature. The dynamics of the dipoles is the key to construct hybrid molecule-based switchable dielectrics by motional changes of polar components at different phases. Furthermore, the dielectric properties have also been mentioned and discussed in great detail.